Valve shock dampener

ABSTRACT

A valve chock dampener for installation at one end of a rocker arm in a linkage for controlling opening and closing of a valve in an internal combustion engine. The dampener includes a housing formed with an open ended piston-receiving chamber and a piston is slidably received in such chamber and is formed with a head end for engaging an adjacent control member for controlling the valve.

United States Patent H 1 Peterson [4 1 Oct. 3, 1972 [54] VALVE SHOCKDAMPENER 1,494,923 5/1924 Lavoie ..123/90.47 [72] Inventor: RexW'Petemn, H591 Davenport 2,434,386 1/ 1948 Bradshaw ..123/90.46 Road LosAlamitos Calif 90720 1,784,767 12/1930 Summers ..l23/90.46 X 2,438,6313/1948 Bergmann .123/90.59 [22] Filed: June 8, 1970 FOREIGN PATENTS ORAPPLICATIONS [21] Appl. No.2 44,211

299,565 11/1928 Great Britain ..123/90 I-I 893,092 4/1962 Great Britain..123/90 H [52] US. Cl. ..l23/90.45, 123/9046, 123/9047,

123/9049, 123/9 Primary Examiner-Al Lawrence Smith Int. Att0rney FulwidePatton Richer Lee & Utecht [58] Field of Search..123/90.45, 90.46,90.47, 90.49,

123/9055, 90.56, 90.58, 90.59, 90.19 [57] ABSTRACT [56] References CitedA valve choclr dampener for installatien at one end of a rocker arm in alinkage for controlling opening and UNITED STATES PATENTS closing of avalve in an internal combustion engine. The dampener includes a housingformed with an MacMlllan p ended piston receiving chamber and a piston i2,411,650 ll/l946 BLlfkl'l?.I'dt Slidably received in such chamber andis formed with 3,140,698 7/1964 Voorhies ..123/90.46 a head end forengaging an adjacent control member 3,024,775 3/1962 Wuest ..123/90.47 Xfor controlling the valve I 2,669,228 2/1954 Bergmann ..l23/90.472,036,936 4/1936 I-lalford ..123/90.46 7 Claims, 5 Drawing FiguresPATENTEDum 3 m2 SHEET 2 BF 2 \NUETQVQN \I, m W A\\w \W A V. w IN MN 1 IMW A I mm A I I x I I l m I I I l u bv I N Av 7" v m A .R R c Mm w IINVENTOR Rex m PE rezso/v BY J 6%) M W v I flrmp/vzns VALVE SHOCKDAMPENER BACKGROUND OF THE INVENTION 1. Field of the Invention:

The present invention relates to a shock dampening device forinstallation in the valve control linkages of heavy duty internalcombustion engines to dampen the shock experienced during reciprocationof such linkages to control the valve.

2. Description of the Prior Art:

Internal combustion engines normally employ valves for admitting fuel tothe piston chambers and such valves are biased to their closed positionby valve springs. A valve control linkage is frequently driven by camsto act on the valves to overcome the bias of such valve springs to openthe valves at selected intervals during the cycle of engine operation.However, because of the thermal expansion of the engine block a selectedamount of valve clearance must be provided thereby resulting in acertain amount of play in the linkage which results in high impactbetween parts upon reciprocation of such linkage during control of thevalve. This is particularly true in the case of heavy duty engines whichemploy relatively massive control linkages and operate at high RPMs andthe problem is compounded by the fact that such linkages frequentlyemploy a ball and socket joint and the repeated impact results in theball and socket joints being hammered out thereby decreasing the degreeof valve opening and resulting in non-uniform opening from revolution torevolution.

Valve control linkages have been proposed which incorporate springs forproviding gradual application of opening force to the stern of a valve.A device of this kind is shown in US. Pat. No. 1,866,293. However, suchdevices suffer the shortcoming that the springs are of insufficientstrength to withstand the heavy loads created at high RPMs for heavyduty engines. Applicant is unaware of any prior art self-contained shockdampeners which employ a piston biased to an extended position in ahousing for maintaining the various joints in the valve control linkagebiased together to thereby prevent spacing in such joints which resultsin excessive shock when engaging members are brought together uponreciprocation during each engine revolution.

SUMMARY OF THE INVENTION The present invention is characterized by ahousing carried at one end of the rocker arm of an internal combustionengine and formed with an open ended chamber which receives a piston.Biasing means is disposed in the chamber for maintaining the pistonbiased outwardly into engagement with the valve stem with sufficientforce to maintain the joints in the valve control linkage biasedtogether during reciprocation of the linkage and to enable the valvespring to overcome such force and drive said piston back in said housingon each down stroke of said valve. Abuttment means is provided in spacedapart relationship on the housingand on the piston for engagement tolimit telescoping of the piston in the housing to overcome the valvespring bias and open the valve on each revolution of the engine.

An object of the present invention is to provide a valve shock dampenerof the type described which is relatively light, self-contained, andreadily installable in a standard internal combustion engine.

Another object of the present invention is to provide a shock dampenerof the type described which can be employed for setting the valveclearance.

Still another object of the present invention is to provide a valveshock dampener of the type described which is self-lubricating.

A further object of the present invention is to provide a valve shockdampener of the type described which provides for automatic take-up ofclearances resulting from thermal expansion of the engine block.

These and other objects and the advantages of the present invention willbecome apparent from a consideration of the following detaileddescription when taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of aheavy duty engine having a valve shock dampener of present inventioninstalled therein;

FIGS. 2 and 3 are vertical sectional views, in enlarged scale, takenalong the lines 2-2 of FIG. 1 and showing the shock dampener in twodifferent positions;

FIG. 4 is a vertical sectional view similar to FIG. 2 of a secondembodiment of the vale shock dampener of present invention; and

FIG. 5 is a horizontal sectional view, in enlarged scale, taken alongthe lines 5-5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, generally,the shock dampener 21 of present invention may be installed on the valveend of a rocker arm 23 included in the valve control linkage of a heavyduty internal combustion engine 25. Engines of this type frequentlyinclude relatively massive push rods 27 which are formed on their lowerextremities with balls 31 received in sockets 33 of a slider 35 which isdriven by a drive cam 37. The valve shock dampener 21 includes ahousing, generally designated 41, which is formed with a downwardlyopening chamber 43 which receives a piston, generally designated 45,that is biased downwardly into engagement with the upper end of aconventional valve, generally designated 47, by means of a coil spring49. The lower extremity of the piston 45 is formed with an enlarged head51 which abutts the lower end 53 of the housing 41 to limit telescopingof such piston upwardly into the chamber 43 whereby such piston ismaintained biased downwardly to maintain the valve control linkage 24under constant bias to maintain the ball 31 biased firmly into thesocket 33 during reciprocation of the valve control linkage to therebyavoid separation thereof which would cause such ball and socket to behammered against one another upon re-engagement thereof thereby causingexcess wear and making close adjustment and control of the valve openingimpossible.

Heavy duty engines 25 generally operate on natural gas and frequentlyhave relatively large cylinder bores 55 which may be twelve inches indiameter and the rocker arms 23 may be 18 inches long and the push rods27 46 inches long. Consequently, the overall size and mass of theequipment creates substantial shock problems during reciprocation of therelatively massive linkage 24. The upper end of the cylinder bore 55includes a valve seat 54 for communicating flow of natural gas from aninlet manifold 52 and upon which the valve poppet 56 of the valve 47seats. Secured to the upper extremity of the valve stem is a springretainer 58 against which the upper end of a conventional valve spring60 seats.

The rocker arm 23 includes bosses 57 and 59 on its opposite ends whichare formed with through vertical bores that are internally threaded forreceipt of externally threaded adjustment studs, such as the adjustmentstud 61 mounted in the boss 59.

Referring to FIG. 2, the housing 41 is in the form of a cylindrical boltwhich is exteriorially threaded for receipt in an internally threadedbore 65 formed in the rocker arm boss 57. A bore projects verticallyupwardly from the bottom end of the housing 41 to form the pistonchamber 43 and is then reduced in diameter to form an internal shoulder69 against which the upper end of the piston biasing spring 49 abutts.The upper end of the vertical bore is again reduced in diameter to forman oil inlet bore 71 that receives a tight fit check valve insert,generally designated 73, in its upper extremity.

The check valve insert 73 is formed with a through vertical passage 75which receives a coil compression spring 77 therein for biasing a checkball 79 upwardly into engagement with a valve seat 81 formed in theupper extremity thereof.

A transverse bore 85 is drilled through the upper extremity of thehousing 41 and receives a cross rod 87 which forms an adjustmenthandle.The cross rod 87 is formed with a reduced-in-diameter portion 89 forpassage of oil thereby.

Still referring to FIG. 2, the piston 45 is formed with an upwardlyprojecting straight shank 93 which has a peripheral O-ring groove formedin the lower extremity thereof for receipt of an O-ring 95. A snap ringgroove 97 is formed in the piston shank 93 for receipt of a snap ring 99which is snapped into a peripheral groove formed in the wall of thehousing 41 to hold the piston 35 captive in the housing or barrel 41.

It is noted that the overall size of the shock dampener 21 is only 1%inch in diameter and 3 inches in length whereby very little, if any,weight is added to the valve control linkage 24 thereby.

In operation, the valve shock dampener 21 of present invention may beinstalled in a heavy engine by merely removing the conventional set studnormally screwed into the boss 57 for adjusting the valve 47 andscrewing the shock dampener 21 into position. If desirable, a lock nutmay be screwed onto the threaded portion of the housing 41 to lock saidhousing into position relative to the rocker arm 23. The valve clearanceis determined by the distance between the top shoulder of the pistonhead 51 and the bottom end 53 of the housing 41 when the drive cam 37(FIG. 1) is projecting downwardly and the poppet 56 of the valve 47 isseated on the valve seat 54. It is suggested that this valve clearancebe set at .010 inches when the engine is cold. Oil is inserted in thepiston spring chamber 43 by depressing the check ball 79 and droppingapproximately 40 drops of SAE twenty or thirty weight oil therein forlubrication and dampening vibration of the piston spring 49.Approximately four to 6 drops of such oil will seep downwardly past theO ring each month so oil should be added periodically.

When the engine 25 is started, the cam shaft 109 will rotate the cam 37to drive the valve control linkage 24 to reciprocate the rocker arm 23causing the dampener 21 to be moved downwardly against the bias of thevalve spring 60 and causing the piston 45 to be forced upwardly againstthe bias of the pistonspring 49 until the shoulder of the piston head 51engages the lower end 53 of the housing41 to thereby overcome the biasof the valve spring 60 and open the valve 47 a selected amount to enablepressurized natural gas to enter the cylinder chamber 55 from the inlet52. In a representative installation the piston spring has a springcoefficient of 24 pounds per inch and the valve spring 60 has a springconstant of pounds per inch.

During the upstroke of the valve 47 the valve poppet 56 will seat on thevalve seat 54 and the shock dampener 21 will continue its upwardmovement thereby enabling the piston spring 49 to bias the piston 45downwardly to maintain contact with the upper end of the stem of thevalve 47 to maintain the right hand end of the rocker arm 23 biasedupwardly to bias the left hand end thereof downwardly and maintain theset stud 61 pressed downwardly against the push rod 27 to maintain theball 31 biased firmly in the ball socket 33 thereby preventingseparation between such ball and socket. Consequently, as the cam 37commences driving the slider 35 upwardly, the ball 31 will already be infirm contact with the ball socket 33.thereby avoiding such ball andsocket being hammered together resulting in deformation and excessivewear.

The foregoing procedure will be repeated during each revolution of theengine 25 and as such engine heats up, the engine block will expandthereby moving the valve seat 54 and rocker arm mounting pin 62 upwardlyrelative to the cam shaft 109. Consequently, the push rod 27 will notmaintain the rocker arm 23 pivoted as far clockwise as when the enginewas cold and at the end of each upstroke of the right hand end of therocker arm the piston 45 will be telescoped further out of the housing53 to maintain tension on the entire valve drive linkage 24 to assurethat-the ball 31 and socket 33 do not separate and then hammer backtogether.

It will be clear that with the dampener 21, the valve clearance definedbetween the piston shoulder 52 and end of he housing 53 may be setrelatively large to assure that the piston 45 telescopes sufficientlyfar into the housing 53 to enable the valve 47 to close fully while theengine is cold. Further, while the engine is cold the piston spring 49biases the piston 45 downwardly with sufficient force to maintain thehousing 53 biased upwardly and the rocker arm 23 rocked counterclockwisewith sufficient force to maintain the ball 31 seated in the socket 33during downward travel of the slider 35.

The combination shock dampener and compensator, generally designated129, shown in FIG. 4, is similar to the shock dampener shown in FIG. 1and includes a barrel which is externally threaded for receipt in arocker arm boss 57.

The shock dampener 129 is formed with a downwardly opening bore 131which has a plunger device, generally designated 135, telescopedthereto. The plunger device 135 is formed on its upper end with anenlarged base 137 having a downwardly projecting bore 139 therein fordefining a hydraulic fluid reservoir. The plunger device 135 includes areduced-indiameter plunger 143 projecting downwardly from the base 137and telescopically received in an upwardly opening bore 147 formed in abarrel defined by the shank 149 of a piston, generally designated 151,and the lower end of the plunger 143 cooperates with the lower extremityof the piston bore 147 to define a takeup hydraulic fluid chamber 155which has fluid supplied thereto through a fluid passage 157 projectingdownwardly therefrom and turning radially outwardly to communicate withan annular passage 161 formed between the periphery of the upper part ofthe piston shank 149 and the bore 131 of the barrel. The plunger 143closely fits the piston bore 147 to define a relatively small annularbleed passage 162 for controlled escape of hydraulic fluid from thereservoir 155.

Fluidflow from the fluid take-up chamber 155 is controlled by a checkvalve ball 165 which is biased downwardly into engagement with a checkvalve seat 167 in the piston 151 by means of a compression spring I 169which projects upwardly into a downwardly opening bore 171 formed in thelower extremity of the plunger 143. The pistonshank 149 is formed with aperipheral retainer groove 175 for receipt of a snap ring 177 snappedinto a groove formed in the barrel 131 of the adapter housing to retainthe piston 151 in the housing. The piston shank 149 is also formed withan annular O-ring groove 181 for receipt of an O-ring 183 which sealsthe hydraulic fluid in the reservoir 139.

The piston 151 is biased downwardly by means of a biasing spring 185coiled around the plunger 143 and abutted on its top end against ashoulder 187 formed by the plunger base 137. A plurality of angularlyextending bores 191 lead from the fluid reservoir 139 to the annularchamber formed between the plunger 143 and housing barrel forcommunicating hydraulic fluid to such chamber and to the annular passage161 leading to the inlet passage 157 to the take-up chamber 155.

The lower extremity of the piston 151 is formed with a piston head 201that defines an upwardly facing shoulder 203 for engagement with thelower end 205 of the adapter housing to thereby positively limit upwardmovement of such piston.

The shockdampener 129 shown in 4 operates similar to the shock dampener21 except that when the engine 25 is cold and the control cam 37 is inits downward position, the piston 151 will be biased to its fulldownward position by the piston spring 185 to telescope such pistondownwardly on the plunger 143 to pull a partial vacuum in the take-upchamber 155 thereby enabling the atmospheric pressure on the fluid inthe fluid reservoir 139 to force such fluid downwardly through thepassages 191, annular passage 161 and in through the inlet passage 157to raise the check ball 155 off the seat 157 against the bias of thecheck valve spring 169 to fill the take-up chamber 155 formed at thebottom end of the plunger 143.

As the control cam 37 rotates upwardly to drive the right hand end ofthe rocker arm 23 downwardly, the dampener 129 will be moved downwardlyto move the plunger 143 downwardly against the hydraulic fluid in thetake-up chamber 155. The check ball 165 blocks such fluid from escapingto the inlet passage 157 and only a relatively minor amount of suchfluid escapes upwardly through the annular bleed passage 162 formedbetween the plunger 143 and piston bore 147. Consequently, separation ofthe ball 31 from the socket 33 is prevented and opening of the valve 47is initiated as soon as the right hand end of the rocker arm 23commences its downward stroke.

On the upstroke of the right hand end of the rocker arm 23, the shockdampener 129 will be raised sufficiently to enable the bias of thepiston spring 185 to urge the piston 151 downwardly to take up any spaceformed between the lower end thereof and the top of the valve stem tothereby again create a partial vacuum in the take-up chamber to draw anyadditional hydraulic fluid past the check valve which is required toreplace any fluid that escaped through the bleed passage 162 on theprevious downstroke.

As the engine 25 heats up and expands, the rocker arm mounting pin 62and the valve seat 54 will be raised relative to the cam 37 therebyincreasing the distance the right hand end of the rocker arm 23 will beraised above the valve seat 24 while the valve 47 is seated, therebyenabling the spring to telescope the piston 151 further downwardlyagainst the top end of such valve to draw greater quantities of fluidpast the ball 65 and into the take-up chamber 145. Again, on thedownstroke of the right hand end of the rocker arm 23 the check ball 151will retain the fluid trapped in the take-up chamber 155 therebymaintaining a firm metalto-metal contact throughout the joints in thevalve control chain 24 and, particularly, between the ball 31 and thesocket 33.

From the foregoing detailed description it will be apparent that thevalve shock dampener of present invention is a self-contained unit whichmay be conveniently installed in a heavy duty engine and will provide along and maintenance free life. The shock dampener maintains firmmetal-to-metal contact throughout the joints in the valve controllinkage to prevent hammering together thereof which would result inerratic valve opening and closing and hammering of the socket and causethe ball to make contact therewith at different points on subsequentstrokes resulting in various degrees of valve opening and rendering itimpossible to set the valve clearance for proper engine operation.Further, the shock dampener of present invention is relatively small insize thereby enabling installation thereof in the valve control linkageof existing heavy duty engines without upsetting the balance thereof andsugnificantly adding to the inertia thereof. Additionally, in case offailure, the adapter may quickly be removed and replaced by aconventional set stud thereby reducing down time for the engine.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention.

lclaim:

1. A self-lubricating shock dampener for installation in the valvecontrol linkage of a heavy duty internal combustion engine that has apredetermined valve clearance and of the type that includes anunlubricated and freely partable control linkage having a rocker armengaging the adjacent end of the valve control member, said dampenercomprising:

a housing formed with an open ended piston-receiving chamber and firstabutment means;

means for mounting said housing on one end of said rocker arm adjacentsaid valve control member;

a piston received in the open end of said chamber and formed with a headend for engaging said one end of said valve control member and withsecond abutment means normally spaced from said first abutment means adistance corresponding to said predetermined valve clearance said pistoncooperating with said housing to form a lubrication-receiving chamberhaving a fluid inlet for receipt of a lubricant;

seal means for sealing said piston with respect to said housing to seallubrication in said lubricationreceiving chamber;

valve means for normally closing said inlet;

bias means in said piston-receiving chamber for bias ing said pistonoutwardly into engagement with said valve control member with sufficientforce to maintain the freely partable links in said linkage biasedtogether to dampen the shock resulting from reciprocation of saidlinkage during operation of said valve.

2. A shock dampener as set forth in claim 1 wherein:

said housing is formed with a hydraulic fluid reservoir and includesplunger means;

said piston is formed with an open ended barrel telescoped over saidplunger means to cooperate therewith to form a take-up chamber at thefront of said plunger means and a relatively small bleed passage leadingfrom said take-up chamber to said reservoir, said piston, further,including an inlet passage leading from said reservoir to said take-upchamber; and w said dampener includes check valve means for per mittingfluid flow through said inlet passage from said reservoir to saidtake-up chamber whereby said biasing means will maintain said pistonextended when said valve is closed to cause said fluid to be drawnthrough said inlet passage past said check valve means to maintain saidtake-up chamber filled sufficiently to restrict telescoping of saidpiston on said plunger means during the subsequent valve opening strokeof said rocker arm.

3. A shock dampener as set forth in claim 2 wherein:

said plunger means is formed to closely fit said barrel and cooperatetherewith to form said bleed passage.

4. A shock dampener as set forth in claim 1 wherein said rocker arm isformed on said one end with a threaded bore and wherein:

said housing is externally threaded for being screwed in said boss.

5. A shock dampener as set forth in claim 4 wherein:

said housing is formed with one extremity defining said first abuttmentmeans; and

said piston is formed with a head having a shoulder defining said secondabuttment means.

6. A shock dampener as set forth in claim 1 wherein said valve is biasedto its closed position with a predetermined force and wherein:

said biasing means biases said piston to its extended position with aforce having a magnitude of approximately 20 per cent of saidpredetermined f 7. A s li ock dampener as set forth in claim 1 whereinsaid rocker arm is formed on its valve end with an internally threadedbore disposed in alignment with the stern of said valve and wherein:

1. A self-lubricating shock dampener for installation in the valvecontrol linkage of a heavy duty internal combustion engine that has apredetermined valve clearance and of the type that includes anunlubricated and freely partable control linkage having a rocker armengaging the adjacent end of the valve control member, said dampenercomprising: a housing formed with an open ended piston-receiving chamberand first abutment means; means for mounting said housing on one end ofsaid rocker arm adjacent said valve control member; a piston received inthe open end of said chamber and formed with a head end for engagingsaid one end of said valve control member and with second abutment meansnormally spaced from said first abutment means a distance correspondingto said predetermined valve clearance said piston cooperating with saidhousing to form a lubrication-receiving chamber having a fluid inlet forreceipt of a lubricant; seal means for sealing said piston with respectto said housing to seal lubrication in said lubrication-receivingchamber; valve means for normally closing said inlet; bias means in saidpiston-receiving chamber for biasing said piston outwardly intoengagement with said valve control member with sufficient force tomaintain the freely partable links in said linkage biased together todampen the shock resulting from reciprocation of said linkage duringoperation of said valve.
 2. A shock dampener as set forth in claim 1wherein: said housing is formed with a hydraulic fluid reservoir andincludes plunger means; said piston is formed with an open ended barreltelescoped over said plunger means to cooperate therewith to form atake-up chamber at the front of said plunger means and a relativelysmall bleed passage leading from said take-up chamber to said reservoir,said piston, further, including an inlet passage leading from saidreservoir to said take-up chamber; and said dampener includes checkvalve means for permitting fluid flow through said inlet passage fromsaid reservoir to said take-up chamber whereby said biasing means willmaintain said piston extended when said valve is closed to cause saidfluid to be drawn through said inlet passage past said check valve meansto maintain said take-up chamber filled sufficiently to restricttelescoping of said piston on said plunger means during the subsequentvalve opening stroke of said rocker arm.
 3. A shock dampener as setforth in claim 2 wherein: said plunger means is formed to closely fitsaid barrel and cooperate therewith to form said bleed passage.
 4. Ashock dampener as set forth in claim 1 wherein said rocker arm is formedon said one end with a threaded bore and wherein: said housing isexternally threaded for being screwed in said boss.
 5. A shock dampeneras set forth in claim 4 wherein: said housing is formed with oneextremity defining said first abuttment means; and said piston is formedwith a head having a shoulder defining said second abuttment means.
 6. Ashock dampener as set forth in claim 1 wherein said valve is biased toits closed position with a predetermined force and wherein: said biasingmeans biases said piston to its extended position with a force having amagnitude of approximately 20 per cent of said predetErmined force.
 7. Ashock dampener as set forth in claim 1 wherein said rocker arm is formedon its valve end with an internally threaded bore disposed in alignmentwith the stem of said valve and wherein: said housing is externallythreaded for being screwed into said internally threaded bore.